Pro- and anti-inflammatory cytokine responses to a 164-km road cycle ride in a hot environment

Immunology of Physical Exercise: Is Equus caballus an Appropriate Animal Model for Human Athletes?

Domestic horses routinely participate in vigorous and various athletic activities. This enables the horse to serve as a model for studying athletic physiology and immunology in other species, including humans. For instance, as a model of physical efforts, such as endurance rides (long-distance running/aerobic exercise) and races (anaerobic exercise), the horse can be useful in evaluating post-exercise response. Currently, there has been significant interest in finding biomarkers, which characterize the advancement of training and adaptation to physical exercise in the horse. The parallels in cellular responses to physical exercises, such as changes in receptor expression and blood cell activity, improve our understanding of the mechanisms involved in the body's response to intense physical activity. This study focuses on the changes in levels of the pro- and anti-inflammatory cytokines and cellular response in the context of post-exercise immune response. Both the direction of changes in cytokine levels and cellular responses of the body, such as proliferation and expression of surface markers on lymphocytes, monocytes and neutrophils, show cross-functional similarities. This review reveals that horses are robust research models for studying the immune response to physical exercise in human athletes.

Ultra-Cycling- Past, Present, Future: A Narrative Review

BACKGROUND

Ultra-endurance events are gaining popularity in multiple exercise disciplines, including cycling. With increasing numbers of ultra-cycling events, aspects influencing participation and performance are of interest to the cycling community.

MAIN BODY

The aim of this narrative review was, therefore, to assess the types of races offered, the characteristics of the cyclists, the fluid and energy balance during the race, the body mass changes after the race, and the parameters that may enhance performance based on existing literature. A literature search was conducted in PubMed, Scopus, and Google Scholar using the search terms 'ultracycling', 'ultra cycling', 'ultra-cycling', 'ultra-endurance biking', 'ultra-bikers' and 'prolonged cycling'. The search yielded 948 results, of which 111 were relevant for this review. The studies were classified according to their research focus and the results were summarized. The results demonstrated changes in physiological parameters, immunological and oxidative processes, as well as in fluid and energy balance. While the individual race with the most published studies was the Race Across America, most races were conducted in Europe, and a trend for an increase in European participants in international races was observed. Performance seems to be affected by characteristics such as age and sex but not by anthropometric parameters such as skin fold thickness. The optimum age for the top performance was around 40 years. Most participants in ultra-cycling events were male, but the number of female athletes has been increasing over the past years. Female athletes are understudied due to their later entry and less prominent participation in ultra-cycling races. A post-race energy deficit after ultra-cycling events was observed.

CONCLUSION

Future studies need to investigate the causes for the observed optimum race age around 40 years of age as well as the optimum nutritional supply to close the observed energy gap under consideration of the individual race lengths and conditions. Another research gap to be filled by future studies is the development of strategies to tackle inflammatory processes during the race that may persist in the post-race period.

Physiological Benefits and Performance of Sea Water Ingestion for Athletes in Endurance Events: A Systematic Review

In different endurance events, athletes have limited access to fluid intake, such as ultra-endurance running. For this reason, it is necessary to establish an adequate hydration strategy for this type of long-duration sporting event. Indeed, it seems that the intake of seawater is a suitable hydration alternative to improve post-exercise recovery in this type of endurance event. This seawater is characterized by being a deep natural mineral water of moderate mineralization, which is usually extracted from a depth of about 700 m. Therefore, the aim of this systematic review is to evaluate the efficacy of seawater consumption in both performance and post-exercise recovery in long-duration sport events. A systematic and comprehensive literature search was performed in PubMed, Scopus, and Web of Science in September 2022. Initially, 8 out of 558 articles met the inclusion criteria. Among these eight studies, six were randomized clinical trials, and two were observational studies (one cross-sectional and one prospective study in well-conditioned student athletes). The results showed that deep sea water consumption accelerated the recovery of aerobic capacity and leg muscle capacity on running performance. In addition, the lactate production after the running exercise in seawater was significantly lower than in pure water. In conclusion, the present review demonstrates that seawater consumption could significantly improve the capacity of recovery after exercise.

Seawater Hydration Modulates IL-6 and Apelin Production during Triathlon Events: A Crossover Randomized Study

A triathlon is an endurance event in which athletes need an efficient hydration strategy since hydration is restricted at different stages. However, it seems that seawater intake can be a suitable hydration alternative for this type of endurance event. Therefore, the aim of this study was to evaluate the efficacy of seawater hydration during a triathlon on cytokine production. Fifteen trained male triathletes (age = 38.8 ± 5.62 years old; BMI = 22.58 ± 2.51 kg/m²) randomly performed three triathlons, one of them consuming seawater (Totum SPORT, Laboratories Quinton International, S.L., Valencia, Spain), the other one consuming tap water ad libitum, and the last a physiologic saline solution as placebo. The triathlon consisted of an 800 m swim, a 90 km bike ride, and a 10 km run. Blood samples were taken at rest and after training, where markers of inflammation, hemoglobin, and hematocrit concentration were assessed. While the seawater was not ergogenic, it significantly increased the release of IL-6 and apelin post-exercise. However, no differences were found between the fractalkine, IL-15, EPO, osteonectin, myostatin, oncostatin, irisin, FSTL1, osteocrin, BDNF, and FGF-21 values over those of the placebo group. The present study demonstrates that hydration with seawater stimulates myokine production, which could lead to improved performance recovery after exercise.

A Single Dose of Ibuprofen Impacts IL-10 Response to 164-km Road Cycling in the Heat

Purpose: The purpose was to determine the effect of a single-dose prophylactic ibuprofen use before a 164-km road cycling event in high ambient temperature on the circulating cytokine and leukocyte responses. Methods: Twenty-three men (53 ± 8 y, 172.0 ± 22.0 cm, 85.1 ± 12.8 kg, 19.6 ± 4.4% body fat) completed a 164-km self-paced recreational road cycling event in a hot, humid, sunny environment (WBGT = 29.0 ± 2.9°C) after consuming 600 mg of ibuprofen (n = 13) or a placebo (n = 10). Blood samples were obtained one to two hours before (PRE) and immediately after (POST) the event, and analyzed for concentrations of circulating cytokines interleukins (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, GM-CSF, IFN-γ, and TNF-α and leukocytes (total leukocytes, granulocytes, monocytes, and lymphocytes). Results: Event completion time was 400.2 ± 74.8 min. Concentrations of all cytokines (except IL-1β, IL-2, IL-5, IL-12, GM-CSF, and IFN-γ) and of all leukocyte subsets increased from PRE to POST. Ibuprofen ingestion attenuated the increase in IL-10 (86% increase with Ibuprofen; 270% increase with placebo). Conclusions: Consuming 600 mg of Ibuprofen prior to a 164-km road cycling event in a hot-humid environment attenuates exercise-induced increases in the concentration of the anti-inflammatory cytokine IL-10, but does not alter the effect of the exercise event on concentrations of other circulating cytokines or leukocyte subset concentrations.

An acute naproxen dose does not affect core temperature or Interleukin-6 during cycling in a hot environment

Non-steroidal anti-inflammatory drugs’ anti-pyretic and anti-inflammatory effects has led some individuals to theorize these medications may blunt core body temperature (Tc) increases during exercise. We utilized a double-blind, randomized, and counterbalanced cross-over design to examine the effects of a 24-h naproxen dose (3–220 ​mg naproxen pills) and placebo (0 ​mg naproxen) on Tc and plasma interleukin-6 (IL-6) concentrations during cycling in a hot or ambient environment. Participants (n ​= ​11; 6 male, 5 female; age ​= ​27.8 ​± ​6.5 years, weight ​= ​79.1 ​± ​17.9 ​kg, height ​= ​177 ​± ​9.5 ​cm) completed 4 conditions: 1) placebo and ambient (Control); 2) placebo and heat (Heat); 3) naproxen and ambient (Npx); and 4) naproxen and heat (NpxHeat). Dependent measures were taken before, during, and immediately after 90 ​min of cycling and then 3 ​h after cycling. Overall, Tc significantly increased pre- (37.1 ​± ​0.4 ​°C) to post-cycling (38.2 ​± ​0.3 ​°C, F_1.7,67.3 ​= ​150.5, p ​< ​0.001) and decreased during rest (37.0 ​± ​0.3 ​°C, F_2.0,81.5 ​= ​201.6, p ​< ​0.001). Rate of change or maximum Tc were not significantly different between conditions. IL-6 increased pre- (0.54 ​± ​0.06 ​pg/ml) to post-exercise (2.46 ​± ​0.28 ​pg/ml, p ​< ​0.001) and remained significantly higher than pre-at 3 ​h post- (1.17 ​± ​0.14 ​pg/ml, 95% CI ​= ​−1.01 to −0.23, p ​= ​0.001). No significant IL-6 differences occurred between conditions. A 24-h, over-the-counter naproxen dose did not significantly affect Tc or IL-6 among males and females cycling in hot or ambient environments.

Dietary Polyphenol and Methylsulfonylmethane Supplementation Improves Immune, DAMP Signaling, and Inflammatory Responses During Recovery From All-Out Running Efforts

Nutritional ingredients with defined mechanisms of action can be useful in the recovery of the body from the physical demands of a habitual training plan. The purpose of this study was to determine the effect of dietary supplementation with optimized curcumin, pomegranate ellagitannins, and MSM (R + MSM) on immune-associated mRNA during early recovery (i.e., up to 8 h post-exercise) following all-out running efforts (5-km, 10-km, and 21.1-km). Subjects (N = 14) were randomized to either a supplement (R + MSM) or a control group using an open label design. The study was completed over a period of 31-day prior to a scheduled half-marathon race. Venous blood samples were collected into PAXgene tubes at baseline, subsequent samples were collected at 2, 4, and 8 h after each running effort. A 574-plex mRNA Immunology Array (NanoString) was measured for each sample and ROSALIND^® Advanced Analysis Software was used to examined changes in 31 annotated immune response pathways and specific mRNA changes. The greatest change in immune pathways occurred at 2 h (GSS > 3) followed by 4 h (GSS 2–3) and 8 h (GSS 1–2). R + MSM was associated with an increase in innate immunity (CAMP, LTF, TIRAP, CR1, IL1R1, CXCR1, PDCDILG2, and GNLY) and a blunted/smaller increase in damage-associated molecular pattern (DAMP) signaling/inflammation (TLR4, TLR5, S100A8, S100A9, and IFP35). We also found changes in immune-associated mRNA that have not been previously linked to exercise recovery (SOCS1, SOCS2, MME, CECAM6, MX1, IL-1R2, KLRD1, KLRK1, and LAMP3). Collectively these results demonstrate that supplementation with a combination of optimized curcumin, pomegranate ellagitannins, and methylsulfonylmethane resulted in changes that may improve biological recovery from all-out running efforts.

Acute moderate-intensity exercise increases total antioxidant capacity and anti-inflammatory responses in competitive cyclists: The role of adiponectin

High-intensity exercise can elicit acute changes in the biochemical and physiological processes in the body of an athlete, including increased oxidative stress and inflammation. The purpose of this study was to explore the effect of acute moderate-intensity exercise on total antioxidant capacity (TAC) and serum levels of anti-inflammatory adiponectin (APN), and inflammatory markers in competitive cyclists. Ten male cyclists (age 15–26 years, body mass index 19.4–24.7 kg/m2) participated in this study. Each subject performed the maximal oxygen uptake test (VO2peak) and completed a 10-min cycling exercise at a workload of 50% of the peak of VO2peak. Blood samples were collected on three different occasions: after an overnight fasting and at the exercise workloads of 50% and 100% VO2peak. We measured APN, TAC, inflammatory markers as well as assessed nutrient and energy intake for each participant. Baseline concentration of serum APN (10.92 µg/mL) significantly increased at 50% and at 100% VO2peak. In addition, TAC also increased after acute exercise (0.079 vs 0.093 nmol/µL). The concentration of APN at 50% VO2peak positively correlated with the CRP ( r = 0.640, p = 0.046) and negatively correlated with TNF-α ( r = −0.696, p = 0.025). This test showed that short (10 min) and medium-intensity (50% VO2peak) exercise activity in trained athletes evoked beneficial antioxidant and anti-inflammatory responses. Importantly, this response correlates with the increase in APN levels thereby showing that highly trained individuals have beneficial responses originating from adipose tissue. Our observations show that a short training at moderate activity can be an important preservative strategy during the recovery training period.

The Role of Inflammation in Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a blinding eye disease which incidence gradually increases with age. Inflammation participates in AMD pathogenesis, including choroidal neovascularization and geographic atrophy. It is also a kind of self-protective regulation from injury for the eyes. In this review, we described inflammation in AMD pathogenesis, summarized the roles played by inflammation-related cytokines, including pro-inflammatory and anti-inflammatory cytokines, as well as leukocytes (macrophages, dendritic cells, neutrophils, T lymphocytes and B lymphocytes) in the innate or adaptive immunity in AMD. Possible clinical applications such as potential diagnostic biomarkers and anti-inflammatory therapies were also discussed. This review overviews the inflammation as a target of novel effective therapies in treating AMD.

Ultra-endurance triathlon performance and markers of whole-body and gut-specific inflammation

PURPOSE

To examine the influence of the Ultraman Florida triathlon (3 days of non-continuous racing; stage 1: 10 km swim and 144.8 km cycle; stage 2: 275.4 km cycle; stage 3: 84.4 km run) on circulating plasma concentrations of whole-body (C-reactive protein (CRP), interleukin (IL)-6 (IL-6), and IL-10 and surrogate gut-specific inflammatory markers (IL-17 and IL-23), and determine whether these variables are associated with performance.

METHODS

Eighteen triathletes (N = 18; 15 men, 3 women; age: 37 ± 8 yrs) were evaluated at baseline and post-race for circulating concentrations of CRP, IL-6, IL-10, IL-17, and IL-23. Blood samples were drawn two days prior to stage 1 (1600 h) and one day after stage 3 (1200 h).

RESULTS

Plasma CRP significantly increased from baseline (1985.8 ± 5962.3 ng/mL) to post-race (27,013.9 ± 12,888.8 ng/mL, p < 0.001, 13-fold increase). Both plasma IL-6 and IL-10 did not significantly change from baseline to post-race. Baseline and post-race concentrations of IL-17 and IL-23 were below detectable limits. Pearson's correlation between mean finish time and post-race IL-10 revealed a significant positive correlation (r = 0.54, p < 0.05).

CONCLUSIONS

Our results suggest that cytokines such as IL-6 and IL-10 involved in the inflammatory response return to near-baseline concentrations rapidly even after ultra-endurance events of extreme duration. The absence of IL-17 and IL-23 may suggest positive gut adaptations from ultra-endurance training. A significant positive correlation between post-race IL-10 concentrations and mean finish time may indicate that a relationship between anti-inflammatory responses and performance exists.

Combined bead-based multiplex detection of RNA and protein biomarkers: Implications for understanding the time course of skeletal muscle injury and repair

Biological response to skeletal muscle injury time course is generally classified as initial (elevated within first 4-h), delayed (elevated at 24-h), and/or prolonged (elevated at 4-h and sustained to 24-h). Accurate description of this process requires the ability to measure a robust set of RNA and protein biomarkers, yet such an approach is not common and not always feasible. This method proposes a novel experimental approach that focuses on the use of bead-based multiplex detection to measure mRNA, lncRNA, cytokines, soluble cytokine receptors, and myokines at 4-h and 24-h post muscle injury. We used an extreme aerobic exercise session (half-marathon race) to create a consistent muscle injury stimulus via oxidative stress and eccentric contractions. Venous blood samples were analyzed to determine the change in 90 targets. Specifically, we identified 14 mRNA, 2 lncRNA, 4 cytokines, and 5 myokines that had only an initial response (change at 4-h). We identified 2 mRNA, 2 cytokines, 13 soluble cytokine receptors, and 1 myokine that had only a delayed response (change at 24-h). Finally, we identified 18 mRNA, 4 lncRNA, 6 myokines and 15 cytokines that had a prolonged response (change at 4-h and sustained at 24-h). We found 4 targets to be undetectable or having no response relative to muscle injury recovery. These findings demonstrate the interplay between RNA and protein biomarkers in response to skeletal muscle injury. This novel experimental application of bead-based multiplexing is applicable to a variety of clinical models that involve muscle injury and/or wasting.